Of course yes. You can add as many themes as you want.
You can modify ur V3i in what u need and according to ur style and mood.
Go to any one of these sites
www.motox.com
www.modmymoto.com
www.motomodders.com.
Here u can find all ur answers. There are many experts who can solve any of your problem.
There are modding GUIDES,THEMES,APPS etc..
You can ask any question about ur v3i. I would recomend u first read the guides and backup ur files before attempting to modify ur v3i.